From d31b6437ac51706221fab1081810ccbdf5fe4d88 Mon Sep 17 00:00:00 2001
From: Rigidity <me@rigidnetwork.com>
Date: Tue, 16 Apr 2024 16:48:42 -0400
Subject: [PATCH] Warn for redundant optionals

---
 crates/rue-compiler/src/error.rs   | 3 +++
 crates/rue-compiler/src/lowerer.rs | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/crates/rue-compiler/src/error.rs b/crates/rue-compiler/src/error.rs
index 9e40d20..f68f81b 100644
--- a/crates/rue-compiler/src/error.rs
+++ b/crates/rue-compiler/src/error.rs
@@ -130,6 +130,9 @@ pub enum DiagnosticInfo {
 
     #[error("cannot check equality on non-atom type `{0}`")]
     NonAtomEquality(String),
+
+    #[error("redundant optional type")]
+    RedundantOptional,
 }
 
 /// Join a list of names into a string, wrapped in backticks.
diff --git a/crates/rue-compiler/src/lowerer.rs b/crates/rue-compiler/src/lowerer.rs
index 6747b8c..23c382b 100644
--- a/crates/rue-compiler/src/lowerer.rs
+++ b/crates/rue-compiler/src/lowerer.rs
@@ -1888,6 +1888,14 @@ impl<'a> Lowerer<'a> {
             .map(|ty| self.compile_type(ty))
             .unwrap_or(self.unknown_type);
 
+        if let Type::Optional(inner) = self.db.ty_raw(ty).clone() {
+            self.warning(
+                DiagnosticInfo::RedundantOptional,
+                optional.syntax().text_range(),
+            );
+            return inner;
+        }
+
         self.db.alloc_type(Type::Optional(ty))
     }